1. Field Of The Invention
The present invention relates to material comminution methods and apparatus. More particularly, the present invention relates to a method and apparatus for reducing bales of pressed wood pulp to loose fiber.
2. Description Of The Prior Art
Highly defiberized and refined wood pulp has many commercial uses such as for absorbent materials in the fluffed condition and the manufacture of articles in the molded or cast condition.
In the past, such pulp has been predominantly shipped to users in bales of highly compressed sheets manufactured by a basic papermaking process. This process generally comprises the slice flow of an aqueous pulp slurry onto a traveling screen for initial water drainage to consolidate a continuous fiber mat or web. Additional water is removed by roll nip pressing and drum drying. At the dry end of the machine, the web is slit and cut into bale section size sheets which are stacked, pressed and wrapped for shipment.
At the conversion point, sheeted bales may be handled by either of two basic techniques for conversion back to pulp. The sheeted bales may be delaminated for relatively low power comminution in the manner taught by U.S. Pat. Nos. 3,692,246, 3,385,531 or 3,938,746. Alternatively, sheeted bales may be bulk shredded by high power machinery such as is taught by U.S. Pat. No. 3,804,340.
In more recent years, processes and machinery have been developed to fluff-dry pulp thereby eliminating the need for sheet forming and cutting. By this means, dry pulp is transported to a baling apparatus which repeatedly fills and presses a dry, fluffed volume unit of pulp. A succession of such pressed volume units laminately build a bale size compacted unit.
Although there are many economic advantages to fluff drying and press baling pulp in this manner, one disadvantage has been the restrictive limitation to high powered bale shredding equipment at the conversion point. If low powered equipment of the type previously described is used, the bales must first be manually delaminated along the naturally occurring planes of a single compressed volume unit. Consequently, savings won by the pulp manufacturer with a more efficient pulp drying and baling process are lost to the converter is increased labor or capital investment.
It is an object of the present invention, therefore, to provide a low powered apparatus for shredding bulk pressed bales of wood pulp.